Nature still represents the richest source of bioactive compounds which can be attractive for medicine as well as crop science. In both areas, the omnipresent development of resistances creates the need for new active principles which can only partly be covered by chemical synthesis.
The genus Penicillium comprises more than 300 species which produce a variety of bioactive compounds. Well-known drug leads from this genus are penicillin antibiotics produced by P. chrysogenum and the antifungal metabolite griseofulvin produced by P. griseofulvum and P. patulum, and several other secondary metabolites have been described from Penicillium species.
For instance, P. citrinum is known for the production of the mycotoxin metabolite citrinin and EP 0 052 366 describes hypocholesterolemic fermentation products of Penicillium citrinum strain ATCC 20606. Penicillium sp. FO-2295, a water isolate, was found to produce a series of anticoccidial compounds, designated as arohynapenes A and B [Masuma, et al., Antibiot. 1994, 47, 46-53] as well as arohynapene D [Tabata, et al., J. Antibiot., 1995, 48, 83-84], but these compounds were reported to show no antimicrobial activity in vitro at a concentration of 1 mg/ml against a number of bacteria and fungi. Further, Penicillium sp. FO-1611, a soil isolate, was found to produce a series of anticoccidial compounds, designated as hynapenes A, B and C [Tabata, et al., J. Antiblot., 1993, 46, 1849-1853]. These hynapenes were also reported to show antimicrobial activity in vitro at a concentration of 1 mg/ml against a number of bacteria and fungi, including Pyricularia oryzae, the anamorph of Magnaporthe oryzae. 
Tanzawaic acids A, B, C and D have been isolated from Penicillium citrinium obtained from the Tanzawa area of Japan, and tanzawaic acids A and B were found to inhibit superoxide anion production in human neutrophils [Kuramoto, et al., Chem. Lett. 1997, 26, 885-886.]. None of tanzawaic acids A, B, C and D was found to show antimicrotubule activity [Kobayashi, et al., Tetrahedron 59 (2003) 455-459]. Tanzawaic acids E and F have been isolated from a Penicillium steckii isolate obtained from an unidentified tunicate [Malmstrom, et al., C. Phytochemistry 2000, 54, 301-309]. Tanzawaic acids G and H have been isolated from a Penicillium citrinium isolate obtained from the inner stem tissues of the Moroccan plant Ceratonia siqua L. [EI-Neketi et al., Journal of natural products, 76(6), 1099-1104. doi:10.1021/np4001366]. However, neither tanzawaic acids G nor H were found to be active against a number of bacteria at a concentration of 64 g/mL. A further Penicillium steckii strain was obtained from saline environment of mangrove plant Avicennia marina and evaluated for antifungal activity in potato dextrose agar against dieback pathogen of rose [Sabat and Gupta, African Journal of Microbiology Research Vol. 4 (3), pp. 126-135, 4 February, 2010].
Although it is well known in the technical field of controlling phytopathogenic fungi to apply biopesticides, such as bacteria or fungi which are not detrimental to the plant or crop to be treated, there is a need for further biopesticides.